The primary characteristic of customized ring back tone service lies in that a piece of melodious music or other especial sound or voice is used to replace the existing tedious ring. When other users call a subscriber who has customized a ring back tone, what they hear will be the customized ring back tone, rather than a conventional ring. The ring back tone service makes mobile operators take the lead in providing individualized and differentiated services and helps to promote corporate images of the operators. The allure of the ring back tone service to individual users lies in that the users may enjoy a sufficiently individualized space, and at the same time, an open network capability.
At present, the ring back tone solutions mainly include intelligent network solutions and non-intelligent network solutions. The intelligent network solutions are widely used, for they are less dependent on network equipment and can be deployed faster.
The existing intelligent network solutions are based on personal ring back tone services, and the ring back tone services provided by operators are substantially directed to the ring back tone services prepaid by individual subscribers. The intelligent network solutions are realized by the Specialized Resource Function (SRF) capacity and the signaling processing capacity of an Advanced Intelligent Peripheral (AIP). The networking of a ring back tone system of the intelligent network solutions is shown in FIG. 1. The symbols are explained as follows:
Service Switching Point (SSP): for triggering a service to a Service Control Point (SCP) and transferring a call to an AIP.
Service Control Point (SCP): for authenticating whether a user has customized a ring back tone service, controlling a calling procedure of the service, and obtaining a Mobile Station Roaming Number (MSRN) and status information of the user from a Home Location Register (HLR), as well as instructing the SSP to route the call to the AIP and completing the play of an individualized ring back tone.
Service Management Point (SMP): for managing the SCP and functioning as a server of MML (Man Machine Language) command.
Advanced Intelligent Peripheral (AIP): for storing codes of a ring back tone customized by a user and ring back tone voice files, playing a ring back tone to a calling party, implementing voice flow of ring back tone customization and management, and providing interfaces for ring back tone customization and management to a Service Provider (SP) via an AIP Web Server.
Service Provider (SP): responsible for providing abundant ring back tone content and providing various means, such as WEB and WAP, for users to manage and customize an individualized ring back tone in a self-supporting way.
According to the networking of the ring back tone system as shown in FIG. 1, a voice channel alternative calling method of a ring back tone is provided in the prior art. A schematic flow chart of this method is shown in FIG. 2, and signaling interactions of this method are shown in FIG. 3. The processes are as follows:
1. A user calls an intelligent subscriber who has activated a ring back tone service, and upon receiving the call, a Mobile Switching Center (MSC) of the calling end connects the call to an SSP according to the number segment or T-CSI (Terminating CAMEL Subscription Information) of the called party;
2. The SSP triggers an intelligent service request by sending an IDP (Initial Detect Point) message to an SCP which the called party belongs to;
3. In the case that the called party is a ring back tone subscriber, the SCP which the called party belongs to initiates an ATI (Any Time Interrogation) to an HLR of the called party and queries a current state of the called party; when the called party is in an idle state, GMSC (Gateway Mobile Switching Center)/MSC/SCP delivers RRBE (Request Report BCSM Event) and CONECT which indicates a special route prefix will be added to the called number; when the called party is in a busy state or a not-reachable state, a Continue message which indicates the call will be continued in the original mode is delivered; and in the case that the called party is not a ring back tone subscriber, the SCP which the called party belongs to delivers a signaling according to signaling specifications of the current network;
4. The SSP routes the call to an AIP based on the route prefix of the called number;
5. The AIP registers the incoming call as a ring back tone service incoming call, removes the route prefix of the roaming number and the parameters such as the number of times the call has been attempted and forwarded, sends an IAM (Initial Address Message) signaling to the called end office and connects the call to an MSC of the called end;
6. After the MSC of the called end pages and finds the called party, the MSC of the called end returns an ACM (Address Complete Message) to the AIP; upon receiving the ACM, the AIP blocks the common ring played by the called end office and plays the ring back tone customized by the called party to the calling party based on such conditions as MSISDN (Mobile Station International ISDN Number) number and calling number;
7. After the called party answers, a reply signal is sent to the AIP; the AIP transparently transmits the reply signal to the calling office, stops playing the ring back tone, and connects the calling voice channel and the called voice channel to start a conversation;
8. After the conversation ends, the called party releases the call first; the SSP reports a hang up event and the SCP releases the call.
According to the networking of the ring back tone system as shown in FIG. 1, a non-voice channel alternative calling method of a ring back tone is provided in the prior art. A schematic flow chart of this method is shown in FIG. 4, and signaling interactions of this method are shown in FIG. 5. The processes are as follows:
1. A user calls an intelligent subscriber who has activated a ring back tone service, and upon receiving the call, an MSC of the calling end connects the call to an SSP according to the number segment or T-CSI of the called party;
2. The SSP sends an IDP message to an SCP which the called party belongs to trigger an intelligent service;
3. The SCP which the called party belongs to delivers a special route prefix according to AIP address information; the SSP routes the call to the AIP based on the route prefix preceding the called number and sends an IAM signaling to the called end office according to the called roaming number to connect the call to an MSC of the called end;
4. The MSC of the called end returns a reply signaling to the SSP and the SSP sends a Play Ring Back Tone instruction to the AIP;
5. The AIP plays a ring back tone to the calling party according to the Play Ring Back Tone instruction;
6. After the called party answers, a reply signal ANM (Answer Message) is sent to the SSP; and the SSP disconnects the link to the AIP and connects the calling voice channel and the called voice channel to start a conversation;
7. After the conversation ends, the called party releases the call first; the SSP reports a hang up event and the SCP releases the call;
8. The call is cleared.
The above two methods are both designed to meet the demand for ring back tone service from individual subscribers, and the demand for ring back tone service from groups after the development of Mobile Virtual Private Network (MVPN) is not considered. Moreover, after a subscriber who has applied for a personal ring back tone joins a group, its personal ring back tone becomes invalid when it acts as a called subscriber in MVPN callings.